Build vs Buy Payment Processing Infrastructure: A Cost, Risk, and Speed Comparison

Every engineering leader who has ever led a fintech startup eventually faces the same question: Do we build our own payment processing infrastructure, or do we buy it from an external provider?

This decision will shape the next several years of your business.

What Payment Processing Infrastructure Actually Involves

Payment processing infrastructure is more complex than most engineering teams anticipate. The technical scope goes well beyond the frontend checkout button.

It involves managing the card processing, acquiring or issuing banks, fraud detection and chargeback platforms, and regulatory compliance with the card schemes.

The acquiring bank is the institution that settles funds into the merchant's account, while the issuing bank is the one that gives the cardholder their card, and any processing stack has to talk to both.

Above them sit the card schemes, Visa and Mastercard, whose rules and certification requirements govern what the stack is allowed to do.

A lot of people jump into the space of building a payment platform, assuming that the technical elements will be manageable.

However, once they are within the space, they understand how deeply involved they will be in a domain that has no shortcuts and requires in-depth knowledge.

Cost Comparison: Building Your Own Payment Processing Infrastructure

Building payment infrastructure in-house means taking on costs that extend well beyond the initial development phase — from upfront licensing to ongoing compliance and eventual re-architecture.

The Upfront Costs

Building your own payment processing infrastructure requires an immediate commitment to the card payment schemes to begin processing transactions. Furthermore, you'll have to take care of licensing with the finance departments and comply with PCI-DSS.

EMI or PI licence: an electronic money institution or payment institution licence, depending on your country, is what legally permits you to hold and move customer funds, and it has to be granted before a scheme will certify you.

PCI-DSS: the card industry's security standard for storing and transmitting cardholder data. Passing its Level 1 audit is a precondition for processing card transactions at volume, not a later clean-up task.

Moreover, finding someone with experience in acquiring and issuing banks will be next to impossible and expensive.

The Ongoing Costs

Beyond the immediate startup costs of building your own system, there are several other costs that will factor into the operational expenses of your business:

Cost Comparison: Buying or Partnering with an External Vendor

In contrast, buying payment infrastructure from a third-party vendor brings a different cost structure — one that shifts many operational expenses off your balance sheet, even if the per-transaction rate is higher.

The cost of buying or partnering with a third-party vendor for your payment processing could be more expensive on a per-transaction basis.

However, the cost of fraud monitoring, chargeback management, certification with the payment schemes, and supporting new payment methods for customers are all costs that will fall on your shoulders if you go in-house.

At the volume of transactions that you will start with when you are in sub-scale, buying or partnering will ultimately cost less in the grand total than if you build your infrastructure in-house.

Speed to Market: In-House Build vs Vendor Timelines

Building your own payment processing infrastructure will take time to build, test, and gain certification from the card payment schemes.

Depending on how much experience your engineers have with acquiring and issuing banks, you might be looking at 12 to 24-plus months to get to market with your own solution.

By contrast, buying or partnering with an external vendor will drastically cut the time it takes for you to start receiving payments from your customers.

Most vendors selling white label payment gateway services can get you up and running in two to four months with PCI-DSS and GDPR compliance built into the go-live process.

Furthermore, if your startup is a fintech company that meets the requirements of the payment card schemes, you can access fast-track implementation programs with discounted implementation fees.

Risk Comparison: What You Own vs What You Transfer

The choice between building and buying payment infrastructure redraws the lines of operational and regulatory responsibility.

Fraud and Operational Risk

When you go in-house to build your own system, you will have complete control over the backend fraud detection platforms. However, the trade-off is that fraud detection tools and services will always be one step behind the criminal efforts to compromise the transaction process with your customers.

Moreover, chargebacks will be your operational team's problem, whereas a vendor absorbs them on the buy side.

You will also have to build a redundant system for your transactions to ensure that if one platform fails, the other can pick up the transactions where it leaves off.

A payment gateway outage stops revenue instantly, so the failover path is not optional infrastructure, and building it doubles part of the stack you have already paid to build once.

Compliance and Regulatory Risk

There is no such thing as a stationary regulatory regime in the payments industry. Every few years, there will be new regulations that come into play with AML, GDPR, PSD2, and the new PSD3 and PSR regulations.

Each one lands on a different part of the stack: AML rules govern how you screen merchants and monitor transactions, GDPR governs how you store customer and cardholder data, and PSD2 introduced strong customer authentication, which is why 3D Secure sits in every European checkout flow.

PSD3 and the accompanying Payment Services Regulation extend those obligations again, which means the compliance work is recurring engineering work, not a one-off project.

If you go in-house, you will have to be versed in all these regulations. However, if you buy or partner with an external vendor, they will be responsible for ensuring that their systems are updated to comply with all regulatory requirements, which is their area of focus and expertise.

The Case for Building Payment Infrastructure In-House

At scale, owning payment infrastructure can shift the unit economics significantly in your favor.

At high transaction volumes, unit economics change in a meaningful way when a business owns the infrastructure behind its payments rather than renting it.

Factors like routing optimization, direct integration with the electronic payment schemes, and margin optimization via the elimination of intermediaries all contribute to an improved economic case for building out the infrastructure in question.

Analysis of the economics of gateways indicates that at transaction volumes of $100 million or more annually, a company can recoup the costs of building a custom gateway in the range of 18 to 24 months.

For companies whose payment offering is a key element of their product offering, building out the infrastructure that relates to payments can be a means of creating a defensible competitive position. A company that owns the technology that routes payments for its platform, or that builds out payout rules that are specific to its technology, can capture value from that ownership.

The Case for Buying Payment Infrastructure from a Provider

For most companies in growth stages, buying is the lower-risk, lower-cost path to accepting payments.

For most companies in growth stages, the engineering effort and compliance requirements for building the infrastructure required to accept payments from consumers will take engineering resources away from the development of the company's main product offering.

Furthermore, many of the leading vendors in the space for payment gateways already offer access to multi-scheme payment processing, alternate payment methods, and even emerging payment methods and technologies like account-to-account payments and stablecoins.

Account-to-account payments move money directly between bank accounts under open banking rules, bypassing the card networks and their interchange fees, and stablecoin settlement is starting to do something similar for cross-border flows.

Both are expensive to build alone and are typically included in a vendor's roadmap at no additional engineering cost to you.

Furthermore, research into over 300 merchants across the globe found that implementing these payment method optimisations can lead to a 30% increase in the revenue of their eCommerce business.

When Fintech Startups Should Build vs Buy

Whether to build or buy payment processing depends on a specific set of conditions, not company size or ambition alone.

Build When These Conditions Are True

For a company to justify building out the infrastructure for its payments system, it must meet each of these conditions:

Buy When These Conditions Are True

A company should buy a payment gateway infrastructure vendor if it meets each of these conditions:

The Hybrid Path: Composable Infrastructure

Build vs buy is not a binary — a modular approach lets you mix both, and migrate gradually.

The decision of whether to build in-house or to buy an external vendor for a company's payment system does not have to be an all-or-nothing decision.

Companies can buy the commodity components of a payment system from a vendor, and build the remaining, differentiated components of that system in-house.

Furthermore, designing a company's system to be modular from the start will allow them to work with their vendor today without committing the company to a long-term vendor relationship tomorrow.

The vendor can be designed to allow for the incremental introduction of proprietary system components according to the needs of the company and its customers.